1. Technical Field
The present invention relates to a screw device and assembly for theft-proofing or making undue thefts of vehicle wheels more difficult. The invention further relates to a motor vehicle with vehicle wheels which have been theft-proofed by means of the screw device being part of the assembly. The invention can be applied on all types of vehicle wheels, which is particularly advantageous when exclusive private cars provided with special rims or the like are concerned.
2. Background Information
Recently, car thefts and other undue thefts such as thefts of vehicle wheels from unattended motor vehicles have become more and more common. Since vehicle wheels are expensive, such thefts result in a significant economic loss for the vehicle owner, particularly if the motor vehicle is provided with exclusive wheel rims with special design or the like.
Therefore, it is desirable to make it as difficult as possible for thieves or vandals to remove vehicle wheels from an unattended motor vehicle. A number of different devices and assemblies which render undue thefts of vehicle wheels difficult have been previously suggested.
For instance, U.S. Pat. No. 3,241,408 (xe2x80x9cthe ""408 patentxe2x80x9d) discloses nuts or screws for retaining vehicle wheels that are reported to prevent thefts, and means for applying or removing such nuts or screws. According to the ""408 patent, a threaded fastener for vehicle wheels has means adapted for engagement with a wrench for applying and removing the fastener from a cooperating threaded member. The means is a frusto-conical body having a relatively flat radial outer face at its small end and a curvilinearly extending channel of substantially constant width in the outer face, forming a continuous, closed figure substantially devoid of straight line portions and of varying curvature. As such, various portions of the closed figure lie at various distances from the axis of the frusto-conical body. In use, a projecting flange formation of the wrench fits within the channel of the means.
Furthermore, United Kingdom Patent No. GB 2 298 691 A discloses an anti-theft device for mounting an object, preferably a vehicle wheel. According to GB 2 298 691 A, unauthorized release of a bolt or a nut is prevented by a freely rotatable, frusto-conical bush fitted over the head of a fastener. Thereby, a ring fits into an annular groove on the outside surface of the head and engages with a corresponding groove on the inside of the bush when in operation. The head of the fastener has an axially projecting section with lobes on its outer surface. Release is possible with a hollow key having a cylindrical portion with an inner surface of a corresponding shape to the lobate section of the fastener. The lobes can be varied in shape so as to ensure that they are individual.
However, it has become evident that previously known devices and assemblies for theft-proofing can be circumvented by thieves or vandals. For example, wheel bolts having heads with specially designed lock grooves or the like that are intended to receive corresponding projecting portions of a special wrench can in many cases still be rotated by means of a slightly small socket or the like that is punched down or pressed down around the head. Special socket wrench sets have been offered for sale and used for this purpose by unauthorized persons.
When supposedly theft-proof wheel bolts have a rotatable bush enclosing the head of the bolt, it has been found that unauthorized persons can drill holes and insert a tool between the bush and the head of the wheel bolt in order to achieve a locking between these. By drilling two holes on both sides of the longitudinal axis of the wheel bolt, the wheel bolts can subsequently be released, for example by means of a shaft with holes in positions corresponding to the two holes, despite claiming to theft-proof.
Accordingly, a first object of the present invention is to provide a screw device for theft-proofing vehicle wheels which solves the above-mentioned problem with the previously known technique, and which prevents unauthorized persons from removing one or several vehicle wheels from an unattended motor vehicle on which the vehicle wheels are retained by means of one or several screw devices according to the invention.
In accordance with the present invention, this first object of the invention is accomplished by means of the screw device having a screw, a sleeve and a lock member. The screw has a head and a threaded portion intended to be screwed into a thread of a wheel hub. Thereby, the threaded portion is intended to be screwed into the thread of the wheel hub via a recess arranged in a central portion of a vehicle wheel. The lock member comprises an endless, smoothly undulating or curved lock groove in its first end, and a coupling portion in its second end for torsionally rigid coupling to the head. The sleeve is designed for being retained between the screw and the lock member after the coupling. The dimensions of the sleeve are adapted to the dimensions of the recess so that regions of the central portion adjacent to the recess encompass substantially entirely and with close fitting a circumference of the sleeve when the threaded portion has been screwed into the thread.
A second object of the invention is to provide an assembly for theft-proofing vehicle wheels by utilizing the screw device according to the invention. This second object is achieved by means of the assembly having a vehicle wheel in which a central portion forms at least one through-opening, a wheel hub with at least one thread for screwing in or out a threaded portion of a screw. The central portion is designed with a recess encompassing the through-opening. The threaded portion is screwed through the recess into the thread of the wheel hub. The assembly further has a key that turns the screw around its longitudinal axis via a lock member, which is coupled to the screw in a torsionally rigid way. The key is designed to fit into an endless, smoothly undulating or curved lock groove in a first end of the lock member. The assembly further has a sleeve that is retained between the screw and the lock member. According to the invention, the dimensions of the sleeve are adapted to the dimensions of the recess so that regions of the central portion adjacent to the recess encompass substantially entirely and with close fitting a circumference of the sleeve when the threaded portion has been screwed into the thread.
A third object of the present invention is to provide a motor vehicle with theft-proofed vehicle wheels. This third object of the invention is achieved by means of the motor vehicle having a plurality of wheel hubs and at least one vehicle wheel that is/are mounted to the wheel hub or hubs by means of at least one screw device according to the invention, and being part of at least one assembly according to the invention.